1. Field of the Invention
Embodiments of the present invention relate to a thin film transistor, an organic light emitting display device including the same, and a method of manufacturing the organic light emitting display device. More particularly, embodiments of the present invention relate to a bottom gate-type thin film transistor having a low contact resistance, an organic light emitting display device including the same, and a method of manufacturing the organic light emitting display device.
2. Description of the Related Art
Thin film transistors (TFTs) may be used, among other things, as switching devices or driving devices. A conventional TFT may include a gate electrode, a semiconductor layer, and source/drain electrodes. Such TFTs may be classified into top gate type TFTs and bottom gate type TFTs according to a location of the gate electrode with respect to the semiconductor layer.
Typically, top gate type TFTs are used in display devices, e.g., liquid crystal display (LCD) devices, organic light emitting display devices, and so forth. A conventional organic light emitting display device may refer to a device that includes a light emitting layer between two electrodes, a pixel electrode and an opposite electrode, one of the electrodes being connected to a TFT. Such a device may have a wide viewing angle, excellent contrast, and rapid response.
The conventional method of manufacturing an organic light emitting display device includes many mask patterning processes, e.g., at least eight mask patterning steps to reach a point of having formed a pixel defining layer on the pixel electrode. Additional mask patterning steps are needed to form an organic emission layer on the pixel defining layer, and to form the opposite electrode on the organic emission layer. Since each mask patterning process includes coating, exposing, and developing steps using photoresist, the method of manufacturing a conventional organic light emitting display device is made more complex and expensive with each additional mask patterning process.